Claims
- 1. The process for preparing a polyamide-imide foam composition which comprises the steps of:
- providing a cyclic tetracarboxylic acid containing a functional imido group and having the formula ##STR3## reacting said compound with a di-isocyanate to produce a polyamide-imide and having the recurring units: ##STR4## wherein "n" is a positive integer, "R" is a radical selected from the group consisting of alkyline and phenylene radicals, which may have alkyl or aryl substituted and "X" is an integer from 1 to 6.
- mixing therewith from about 1% to 3% of a tertiary amine based on the diisocyanate,
- adding thereto and mixing from about 1.0 to 5.0 parts by weight of an organic diisocyanate per part of the imidocarboxylic acid, and
- adding thereto and mixing from about 2 to 8 weight % water, based on the imidocarboxylic acid.
- 2. The process according to claim 1 wherein said cyclic tetracarboxylic acid containing a functional imido group is prepared by mixing together at a temperature of from about 25.degree. to 250.degree. C. an aromatic dianhydride and an oximine, the mole ratio of oxoimine to dianhydride being from about 0.1:1 to 10:1.
- 3. The process according to claim 2 wherein the ratio of oxoimine to dianhydride is about 1:1 and a monoimidecarboxylic acid is obtained.
- 4. The process according to claim 2 wherein the ratio of oxoimine to dianhydride is about 2:1 and a bisimidocarboxylic acid is obtained.
- 5. The process according to claim 1 wherein from about 1.0 to 20 wt %, based on the imidocarboxylic acid, of a surfactant is added to the mixture prior to addition of the water, whereby a foam of improved cellular uniformity results.
- 6. The process according to claim 5 wherein said surfactant is a silicone surfactant.
- 7. The process according to claim 1 wherein from about 1.0 to 5.0 wt %, based on the diisocyanate of a metal salt catalyst is added to the mixture prior to the addition of the water, whereby foaming is accelerated.
- 8. The process according to claim 7 wherein said metal salt catalyst is selected from the group consisting of tin oxide, tin acetate, dibutyl tin diacetate, zinc chloride, cobalt acetate, boron fluoride and mixtures thereof.
- 9. The process according to claim 1 wherein said mixture is heated to a temperature of from about 50.degree. to 100.degree. C. prior to addition of the water, whereby foaming is accelerated.
- 10. The process according to claim 1 wherein said imidocarboxylic acid is selected from the group consisting of benzophenonetetracarboxyimidocaproic acid monoanhydride, benzenetetracarboxyimidocaproic acid monoanhydride, benzophenonetetracarboxy-bisimidocaproic acid, benzenetetracarboxy-bisimidocaproic acid, and mixtures and oligomers thereof.
- 11. The process according to claim 1 wherein said organic diisocyanate is selected from the group consisting of 1,6 hexamethylene diisocyanate, 2,4 toluene diisocyanate, 4,4' methylenediisocyanate, methylenediisocyanate, a polymeric isocyanate available from Upjohn under the PAPI 94 designation and mixtures thereof.
- 12. The process according to claim 1 wherein said tertiary amine is selected from the group consisting of N-methyl morpholine, triethyamine, diethylcyclohexylamine, dimethylethanolamine and mixtures thereof.
- 13. The process according to claim 1 further including the step of adding a fire retardant composition to the mixture prior to the addition of the water.
- 14. The process according to claim 13 wherein said fire retardant composition is selected from the group consisting of aluminum hydroxide, zinc borate, tricresylphosphate, triphenyl phosphate, chlorotrialkyl phosphate, fully cured polyimide powder and mixtures thereof.
Parent Case Info
This is a division of application Ser. No. 744,419 filed June 13, 1983.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
4546115 |
Gagliani et al. |
Oct 1985 |
|
Divisions (1)
|
Number |
Date |
Country |
Parent |
744419 |
Jun 1985 |
|